Oval Invincibles 151 for 5 (Billings 76*) beat Trent Rockets 148 for 7 (Munro 36, Gregory 35, Zampa 2-20, T Curran 2-31) by five wickets

Billings, who had endured a lean tournament with the bat - averaging 12.5 in his previous seven innings - rediscovered form just in time to rubber-stamp top spot in the table and an automatic place in Sunday's final.

Billings completed the win with a six off Ish Sodhi to leave the Rockets' hopes of defending their crown hanging by a thread.

The Rockets opted to bat after winning the toss but none of their top-order batters managed to build on useful starts.

Alex Hales was first to go, holing out to deep third and Joe Root - having reverse-ramped Spencer Johnson for six - was undone by a ball that skidded through to hit the top of middle and off.

Zampa eventually broke the stand, tempting Munro with a slower ball that he skied to mid-off and Tom Curran made amends for his earlier fumble during the next set as Gregory top-edged a paddle to Billings.

A late flurry of boundaries by Daniel Sams, with 19 from nine, boosted the Rockets in the death overs but their total looked unlikely to seriously trouble the home side, particularly after Jason Roy made early inroads with 19 from 13.

Yet Roy's wicket was the first of three to fall in as many deliveries, including two to Sams as Sodhi took a stunning one-handed catch at full stretch to dismiss Tawanda Muyeye and Sam Curran was castled by the next.

However, Jacks - who had only faced two of the first 20 balls - steadied the ship by drilling Luke Wood over cover for two sixes and Billings then seized control, hammering Sodhi twice into the upper tier at the Vauxhall End.

Billings picked out the gaps expertly, pulling Matt Carter for successive fours, but the stand ended when Jacks chopped on to Sam Cook and Jimmy Neesham's departure followed with 48 still required.

But Tom Curran kept his captain company with an unbeaten 18 and Billings finished the job in style, with eight balls unused.